Merge pull request #3804 from rudycelekli/fix/context-boundary-sequence-20261021

fix(memory): keep new messages beyond cleared context boundary

agent/memory/conversation_store.py

@@ -867,6 +867,16 @@ class ConversationStore:
                         (aid, session_id),
                     ).fetchone()
                     next_seq = row[0] + 1
+                    # Deleting old turns can lower MAX(seq) below a cleared
+                    # context boundary. New messages must remain visible even
+                    # when those deleted sequence numbers would be reusable.
+                    boundary = conn.execute(
+                        "SELECT context_start_seq FROM sessions "
+                        "WHERE agent_id = ? AND session_id = ?",
+                        (aid, session_id),
+                    ).fetchone()
+                    if boundary:
+                        next_seq = max(next_seq, boundary[0])
 
                     inserted = 0
                     for msg in messages:

tests/test_context_boundary_after_delete.py

@@ -0,0 +1,57 @@
+"""New replies stay usable after deleting history below a cleared boundary."""
+
+import sqlite3
+
+import pytest
+
+from agent.memory.conversation_store import ConversationStore
+
+
+@pytest.mark.parametrize("agent_id", ["", "helper"])
+@pytest.mark.parametrize("operation", ["edit", "delete", "regenerate"])
+def test_append_after_deleting_cleared_turns_remains_in_context(
+    tmp_path, agent_id, operation
+):
+    path = tmp_path / "history.db"
+    store = ConversationStore(path, agent_id=agent_id)
+    store.append_messages(
+        "chat",
+        [
+            {"role": "user", "content": "old question one"},
+            {"role": "assistant", "content": "old answer one"},
+            {"role": "user", "content": "old question two"},
+            {"role": "assistant", "content": "old answer two"},
+        ],
+    )
+    assert store.clear_context("chat") == 4
+    if operation == "edit":
+        assert store.delete_message_pair("chat", 0, cascade=True) == 4
+    elif operation == "delete":
+        assert store.delete_message_pair("chat", 2) == 2
+    else:
+        assert store.delete_message_pair("chat", 2, delete_user=False) == 1
+    new_messages = [
+        {"role": "user", "content": "new request"},
+        {"role": "assistant", "content": "new answer"},
+    ]
+    store.append_messages("chat", new_messages)
+    assert store.load_messages("chat") == new_messages
+    assert store.get_context_start_seq("chat") == 4
+    with sqlite3.connect(path) as connection:
+        rows = connection.execute(
+            "SELECT seq FROM messages WHERE agent_id = ? AND session_id = ? "
+            "AND content IN (?, ?) ORDER BY seq",
+            (agent_id, "chat", '"new request"', '"new answer"'),
+        ).fetchall()
+    assert rows == [(4,), (5,)]
+
+
+def test_new_append_does_not_reintroduce_retained_cleared_history(tmp_path):
+    store = ConversationStore(tmp_path / "history.db")
+    store.append_messages("chat", [{"role": "user", "content": "cleared secret"}])
+    assert store.clear_context("chat") == 1
+    current = [{"role": "user", "content": "fresh"}]
+    store.append_messages("chat", current)
+    assert store.load_messages("chat") == current
+    store.append_messages("other", [{"role": "user", "content": "unrelated"}])
+    assert store.latest_seq("other") == 0